The Ringhals Nuclear Power Plant is an icon in Sweden, a symbol of the country’s reliance on nuclear power. The country receives about 40% of its electricity from nuclear reactors—about 20% of that from Ringhals’ four units—and despite government calls for the country to receive all its power from renewable sources by 2040, there remains the possibility of replacing older units with new reactors at existing sites.
The retirement of nuclear reactors in Sweden, at the same time other units are being modernized, spotlights the transformation of the country’s nuclear generation, and Sweden’s electricity production as a whole. Vattenfall, considered the largest energy company in the Nordic electricity market, and the operator of the Ringhals and Forsmark nuclear plants in Sweden, has noted the same negative financial impacts as other nuclear operators worldwide, in an environment of low power prices and increased competition from power sources such as natural gas and renewables. Vattenfall already has said it will close Units 1 and 2 at Ringhals in the next few years, and has entered the renewable market in a substantial way, with more than 1,000 wind turbines in five countries, generating almost 6 TWh of electricity in 2016.
Vattenfall is moving toward a “fossil-free future”—a 2017 presentation to investors promised that “We will help power our customers to live free from fossil fuels within one generation”—that includes growth in renewables while maintaining “efficient operations within hydro and nuclear power.” Among its goals: “Reduce costs and improve operational efficiency.” Vattenfall’s modernization has moved forward in earnest and will be helped by the end of a tax on installed nuclear capacity in Sweden, which was abolished by the country’s parliament in June 2016 and is being phased out over a two-year period.
Results already are being recognized, as evidenced by record electricity output at Ringhals. Upgrades at the plant, even with the finish line for Units 1 and 2 in sight, have paid off with historical achievements in power production, particularly for Unit 4, which is recognized by POWER as a top plant for its output and efficiency, against the backdrop of a difficult economic environment.
Records for Output, Availability
Ringhals, with three pressurized water reactors (Units 2, 3, and 4) and one boiling water reactor (Unit 1), is located on the Varo Peninsula about 37 miles south of Gothenburg. It employed about 1,500 workers at the start of 2017. Vattenfall announced in 2015 plans to close the 881-MW Ringhals 2 unit in 2019, followed by the closure of the 865-MW Ringhals 1 in 2020, saying the remaining life of those units is too short to justify investment in required upgrades to those reactors due to the outlook for continued low electricity prices.
Upgrades that have occurred at the plant have helped Vattenfall’s effort to make Ringhals a model of efficiency, and in 2016, Units 1 and 4 each set records for the amount of electricity delivered, with Ringhals 1 delivering 6.5 TWh and Ringhals 4 delivering 8.3 TWh. The Ringhals 4 output is the highest from a single block since the plant came online in the mid 1970s; the unit completed a power uprate from 940 MW to its current 1,113 MW in 2015. Ringhals delivered an availability of 98% during winter 2016–2017, with availability at 99.9% from January to March of this year.
“The first half of 2017 has been safe and stable production and thus kept pace with 2016, but we are having longer annual [maintenance] outages this year, and due to the past successful production season, we are having longer coast-down periods this year,” Ulf Bernstrom, head of communications at Vattenfall, told POWER. Bernstrom noted in August that Unit 4 had just begun its annual maintenance outage period, and said the unit “has broken another ‘personal’ record regarding production volume for a season between two annual outages,” with availability of more than 96%.
“Well-performed outages are the foundation for safe and stable operation,” Goran Molin, head of production at Ringhals, told POWER. “For Unit 4, 2016 was also the first full year with max upgraded power, which contributed greatly [to its record output].”
Molin said there are many reasons for Ringhals’ success as a power plant, including the accomplishments of Unit 4. “Ringhals [has] a policy to have all know-how on-site,” he said. “We have for instance project and design departments on-site. We do refueling with [our] own personnel. We have bid workshops for mechanical, electrical, and [instrumentation and control] maintenance.
“We are also organized closely together with another big nuclear power plant in Sweden, Forsmark, and have natural and intensive knowledge-sharing and cooperation. On top of this we have the benefit of the Swedish culture, with a natural questioning of any anomalies.”
The economics of nuclear power in Sweden were greatly impacted by the country’s tax on nuclear production, which raised about $484 million in 2015. When Vattenfall announced in mid-2015 it would close Units 1 and 2 at Ringhals about five years ahead of its original schedule—Unit 1 was commissioned in 1976, Unit 2 in 1975, and both were set to be retired by 2025—Germany’s E.ON already was ending production at its 638-MW Oskarshamn 2 reactor, and announced the closing of its 473-MW Oskarshamn 1 (which shut down in June 2017). The E.ON reactors were the oldest in the country; Oskarshamn 1 was commissioned in 1972, and Oskarshamn 2 began service in 1975.
When the Swedish government and opposition parties in June 2016 agreed to the goal of 100% renewable energy by 2040, they were quick to point out that did not mean nuclear plants would close. “This is a goal, not a cut-off date that would prohibit nuclear power, and it does not mean either the end [or] a closure of nuclear power,” Ibrahim Baylan, the country’s energy minister, said at the time. “This is a traditional Swedish compromise”—a compromise that also led to the end of the tax on nuclear power, which means Vattenfall can focus on its modernization strategy with fewer financial restrictions.
“Planning for a power upgrade for Unit 4 (Figure 1) began in 2004 with a feasibility study,” said Molin. “It ended up with two main deliveries, one from AREVA and one from Alstom. During 2008 until 2011 we replaced the six low-pressure turbines, brought in two high-pressure turbines, two 20/400 kV transformers, two generators, new low-pressure preheaters, and a lot of modified piping in the turbine island. On the reactor side, we have replaced the three steam generators as well as the pressurizer.
“Finally, in 2015 we made a modification of the high-pressure preheaters and after that we were ready to perform a test period at max upgraded power.”
Molin noted that the units at Ringhals “have been modified a lot” over the years since their first synchronization to the power grid. “All units have been power upgraded in the range of 9% to 18.6%,” he said. “Additionally, we have done safety upgrades. During the last 10 years we have seen new safety requirements that have been fulfilled, and are currently preparing for the latest [safety measure], which is independent core cooling that shall be in operation before January 1, 2021, in all Swedish nuclear power plants.”
Other upgrades at the plant include replacement of 6-kV and 500-V switchgears, and replacement of instrumentation and control systems. Molin said upgrades at Units 3 and 4 include work on the ABB Combimatic relay system, the Westinghouse DPF control system, modernization of the Foxboro Spec 200 reactor protection system, and an upgrade of the ABB 800XA platform to secure the system for long-term operation.
The recent accomplishments at Ringhals, particularly the success of Unit 4, may take some of the sting out of the closures of the plant’s other two units. “Ringhals 1 and 2 will [be] closed as planned [in] 2019 and 2020 due to profitability reasons,” said Molin. “For Ringhals 3 and 4 there is another situation. We are planning for a lifetime of 60 years [for those units], so we are approximately halfway through their operation. There is broad-based political support in Sweden for operating the existing nuclear plants until the end of their lifetime.” ■
—Darrell Proctor is a POWER associate editor.